Engineer Mehdi Sadaghdar makes YouTube videos in which he answers questions about electronics and technology. One question he apparently gets quite often is which type of electricity hurts more, AC or DC? You have to respect the commitment Sadaghdar has to his audience. To answer the question, he applied increasingly potent electrical shocks… to his tongue.

In AC, or alternating current, the flow of electrons periodically reverses. DC (direct current) is simply unidirectional flow of electric charge. Most electrical systems in the world run on AC (50-60Hz), but many devices require DC power. In these cases, a power supply steps the power down to DC. If you’re tinkering with electronics, there are plenty of places you could get a nasty jolt from either form of electricity.

Sadaghdar wanted to figure out which type of shock would be more painful, but without using huge (read: dangerous) amounts of voltage. It stood to reason he should use the body part with the lowest resistance, which turned out to be his tongue. There are a few incidents during the testing process, which should serve to remind you not to try this at home.

With DC, Sadaghdar started at 1 volt and ramped it up to 12 volts, where he was forced to stop. Before the actual AC testing got underway, Sadaghdar demonstrated how the frequency of AC causes the muscles of the tongue to contract. It’s an effective visual aide. As for how painful 60Hz AC is, he had to stop at about 6.5 volts.

So there you have it. In the case of this one intrepid YouTuber, AC electricity is about twice as painful as DC. Anything for science, right?